New - Magic sign-in links
- Surfaces emailed sign-in links ("magic links"), not just verification codes. When a login email sends a link instead of a code, you get a "Sign-in link" notification with one-click Open link and Copy link from both the toast and the toolbar popup.
- The destination host is shown before you open it, links open only on an explicit click, and only https links are surfaced - so you can see where a link goes first.
- Works with HTML-only emails too, where the link lives only in a button.

Fixes
- More reliable mailbox detection: entering your full webmail URL (including a /SOGo path) in settings no longer stops the watcher from running - the address is now normalized automatically.